What is the surface area of a cone when the slant height is 6 mm and the diameter is 4 mm?

A. 12 mm2

B. 24 mm2

C. 31.4 mm2

D. 50.24 mm2

Diameter of cone = d = 4mm

So,

Radius of cone = r = 2mm

Slant Height = l = 6mm

Surface Area = A = ?

formula for the surface area of cone:

A = pi r (r+l)

Using the values, we get:

A = pi (2) (2+6) = 16 pi mm²

so the correct answer is D